What "tells" have you noticed for AI-generated text (i.e., typical words/phrases, or other patterns indicative of GenAI)?

"In today's ever-evolving [BLANK] environment," three attributes in a row, "BLANK, not BLANK", the cursed em dash.

The inclusion of Markdown ASCII prepending or wrapping of words and phrases

i.e.
# for headings
* for bullet lists
** bold **
etc... etc...

In AI outreach on behalf of direct sales or business development, or even recruiters, it is very clear it is AI-generated when the context is way off - referencing old company associations or completely misunderstanding my role and therefore my interests. There is also over emphasis to "connect emotionally" on something random. Often the text includes hallucinations. The quality is just not there. 

+1 on everything mentioned already. My additional take is when the headers or titles of a paragraph are filled with each word starting with a capital letter.

Like many have stated, the excessive use of em dashes is definitely the most obvious tell.  On social media posts, I also feel like these are obvious:
 - a list of 3 items with emojis at the beginning
- buzzwordy closing statements (e.g. after all, you want clarity, not chaos)
- never more than 2 sentences together without a space